对比剂剂量对裸鼠DCE-MRI成像及定量参数测定影响的研究

摘要

Objective To discuss the animal experiment effect of contrast medium dosage on measurement of the semi-quantitative and quantitative parameters of dynamic contrast-enhanced MRI ( DCE-MRI) , and to optimize the contrast injection dosage in nude mice. Methods 20 nude mice were randomizedly divided into 4 groups (5 animals per group). DCE-MRI was performed in all animals in four different diluted contrast medium dosagcs(0. 05 mmol/kg,0. 10 mmol/kg,0. 30 rnmol/kg and 0. 50 mmol/kg). Signal intensity-time curvc(STC) was drawn, semi-quantitative parameters,was calculated, including peak height (PH), time to peak (TIP), maximum slope of increase (MSI), signal enhancement ratio (SER) ,and quantitative parameters, including microvascular permeability transfer constant (Ktrans) , volume fraction of the plasma space (Vp) , cxtravascular extracellular volume fraction (Vc) , microvascular permeability reflux constant (Kcp) were comparative analysed. Results Ktrans,Vc,Vp and MSI were the highest,TTP was the shortest in 0. 30 mmol/kg group, and there was a statistically significant difference between the groups. Ktrans was positively correlated with MSI(r=0. 539,P= 0. 002), and negatively correlated with TTP (r= - 0. 496 ,P = 0. 005) ; Vp was negatively correlated with TTP(r= -0. 521 , P = 0. 003). Conclusion The contrast medium dosage has certain influence to measure parameters of nude mice in DCK-MRI. With the increase of contrast medium dosage, STC is well fitted in with the semi-quantitative parameters. The dose of 0. 30 mmol/kg may serve as the optimized dosage for quantitative parameters.%目的 通过动物实验明确对比剂剂量对裸鼠动态增强扫描(DCE-MRI)中半定量及定量参数测量的影响,并优选最佳对比剂注射剂量.方法 20只裸鼠随机分为4组,分别以浓度稀释至0.06M后的4种对比剂剂量(0.05 mmol/kg、0.10 mmol/kg、0.30 mmol/kg、0.50 mmol/kg)进行DCE-MRI成像,引入信号强度-时间曲线,对裸鼠后肢肌群的半定量参数(峰值强度PH、达峰时间TTP、信号最大上升斜率MSI、增强率SER)及定量参数(血浆容积分数Vp、血管外细胞外容积分数Ve、体积转运常数Ktrans、反流速率常数Kep)进行对比研究及相关性分析.结果 0.30 mmol/kg组的Ktrans、Ve、Vp及MSI最高,TTP最低,与其他各组间存在统计学差异(P＜0.05);Ktrans与MSI呈正相关(r=0.539,P=0.002);与TTP呈负相关(r=-0.496,P=0.005);Vp值与TTP呈负相关(r=-0.521,P=0.003).结论 对比剂剂量对裸鼠DCE-MRI各项参数的测定具有一定影响,在半定量参数中,随着对比剂剂量的增加,信号强度-时间曲线拟合效果较好;而对于定量参数的测定,对比剂浓度0.06M时,0.30 mmol/kg为优选的裸鼠DCE-MRI对比剂注射剂量.